Receiver control



M'. A. RABKIN RECEIYER CONTROL" Filed Oct. 17, 1930 3 Sheets-Sheet l T0 ANTENNA INVENTOR Moms A. RABKlN BY 7 ATTORNEY May 12, 1936.

M. A. RABKIN RECEIVER CONTROL 3 Sheets-Sheet 2 Filed Oct. 17, 1930 INVENTOR MORRIS A. RABKIN BY ATTORNEY May l2, 1936. M. A. RABKIN RECEIVER CONTROL Filed Oct. 17/ 1950 3 Sheets-Sheet 3 70 AMEN/v4 mmnllmlmmm INVENTOR MORRlS A. RAMON AT'FORNEY Patented May 12, 1936 UNITED STATES PATENT OFFICE RECEIVER CONTROL Delaware Application October 17, 1930, Serial No. 489,274

11 Claims.

The present invention relates to the control of radio receivers, and more particularly to novel methods of, and means for, selecting desired broadcast stations, and adjusting the characteristics of the received signals.

In practically all the receiving sets of present day construction it is necessary to operate a plurality of independent and separate instrumentalities to adjust the various electrical characteristics of the set to a desired state. Thus, such diverse elements as tuning, volume and tone adjustments are operated by separate, manually operable controls thereby particularly detracting from optimum enjoyment of broacast reception.

It is a prime desideratum of my present invention to adjust such diverse controls by manipulating only a single instrumentality whereby a true uni-control arrangement for a radio receiver is provided. I

Another important object of the invention is to provide a radio receiver with uni-control means for selectively, or simultaneously, adjusting its various electrical characteristics.

Another object of the invention is to provide, in combination with a plurality of instrumentalities of diverse electrical characteristics, a

mechanical, unitary means for adjusting one of said instrumentalities upon being subjected to manipulation in a given direction, and for adjusting a different instrumentality upon being subjected to manipulation in a different direction, and adjusting said plurality of instrumentalities by a combination of said last mentioned manipulations.

Still another object of the invention is to provide a simple and efiicient construction whereby the manipulation of a plurality of controls in a radio broadcast receiver can be effected with ease, both from the viewpoint of the ease of control and mechanical operation, requiring a minimum number of parts which are compact in their assembly and extremely durable, whereby the construction is reliable and efficient in operation.

The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims, the invention itself, however, as to both its organization and method of operation being best understood by reference to the following description taken in connection with the drawings, in which I have indicated diagrammatically several arrangements whereby my invention may be carried into effect.

In the drawings,

Fig. 1 is a side elevation of the device, partly in section,

Fig. 2 is a front elevation of a detail of Fig. 1, partly in section,

Fig. 3 is a plan view, from the rear of the panel, of a detail of Fig. 1,

Fig. 4 diagrammatically shows the manner of 5 connecting the device of Fig. 1 in a radio receiver circuit,

Fig. 5 is a side elevation of a modified form of the invention,

Fig 6 is a front elevation of the arrangement in 10 Fig. 5, taken along line 66, in the direction of the arrows,

Fig. '7 is a side elevation of still another form of the invention,

Fig. 8 is a plan view of the arrangement in Fig. 15

7, taken along the line 88, in the direction of the arrows,

Fig. 9 is a front elevation of a portion of the panel of Fig. 7.

Referring to the accompanying drawings in which like characters of reference indicate the same parts in the different views, Fig. 1 shows a portion of a radio broadcast receiver and illustrates one form of control adjustment according to my invention, the panel board I of the receiver being shown only in part for the sake of simplicity of description. As is well known to those skilled in the art, the modern broadcast receiver employs a plurality of tuned radio frequency amplification stages, conventionally represented in Fig. 4, each of the stages embodying a variable condenser and the rotors of all the variable condensers being mounted upon a single shaft, which shaft is designated by the reference numeral 2 in Fig. l, and which assembly of variable conthe shaft 2 by a sleeve 6, by any means well known in the art.

The lever arm, or bell-crank, 4 thus provides a link between the tuning instrumentality of the radio receiver and the manipulable means, now

to be described. The last mentioned means is shown as a sphere 1, preferably of dielectric material such as a phenol-condensation product, which, while shown solid, may be hollow, and which sphere is mounted for universal movement upon a bearing ring 8. The latter ring is mounted for rotation about an axis formed by a line connecting a pivot I], mounted in a bearing I0, and a second pivot 9 mounted in a bearing Ill. The line connecting pivots 9 and 9 is approximately at an angle of 45 degrees to the rear of the panel I, it being observed that the base of each pivot is rigidly affixed to diametrically opposed points on the outer circumference of the ring 8. h

At an angular distance of 90 degrees from the pivots 9, 9, along the inner circumference 8' of the ring 8, there are provided two additional, diametrically opposed pivots I I and I', the base of each of these latter pivots being rigidly affixed to diametrically opposed points of the inner circumference 8' of the ring, while the points, or

noses, of these pivots are set into preferably conical bearing portions I2 in the body of the'sphere. In Fig. 2, the particular manner of mounting the sphere I on the pivots II and II is shown, the sphere, being represented partly in section, having portions thereof cut away by planes oblique to the equatorial region thereof.

As shown in Fig. 1, a portion of the surface of sphere I is disposed in an opening I, which opening is provided in the panel I whereby better use of the receiver is possible. The sphere I is provided with a surface adapted to mesh with the rack 5, and a diametrically opposed rack I3. The

racks Sand |3 are turned 90 degrees apart and the spherical control knob is enabled to mesh vnth racks 5 and I3 for the reason that its surface is made up of a series of successive circles of teeth I4. In Fig. 2, the arrangement of these teeth is shown in further detail, and it will 'be observed that they are so arranged on the surface of the circle that, when sphere is rotated about an axis connecting the pivots 9, 9, a segment of a circle of teeth will mesh with the teeth I5 of the rack 3, while the teeth 20, disposed in the spaces I6 between the teeth I! of the rack, are moved, through it in a direction parallel to the shaft 2.

Conversely, when the sphere I is rotated about an axis connecting the pivots II and II, the teeth of the sphere I, positioned in the spaces I5 between the teeth I5 of the rack I3, will pass throughthe spaces in a direction normal to the length of the rack I5, while the teeth I4 disposed in the spaces I6 of the rack 5 will move into contact with the teeth- I! of the rack 5, and cause the latter to move in the direction of rotation of the sphere, thereby moving the rotors 3 of the gang condenser.

The rack I3 is provided on its surface with a groove portion 28 along the length thereof, the rack being mounted for sliding movement along a track 2| made of insulation material. Thus,

' when the control sphere is manipulated'to cause movement of the rack 3, the latter is reciprocated along the track 2|, the track being secured, by an oblique portion thereof, to panel I by riveting, or any other well known means. It will be observed that the plane of the track 2| is set at such an angle to the panel I that it enables the rack I3 to be moved in a plane disposed at an angle of 90 degrees to the plane of motion of the rack 5.

The track 2| is disposed between the bars 22 and 26, as shown in Fig. 3. Bar 22 is made of dielectric material and is provided with a winding of a conductor 23, the winding being adapted to have the contact 24 slide thereover, the contact 24. being secured adjacent one end of' the rack l3 by any well known means. The bar 22 is maintained in aplane parallel to the plane of the track 2| by an arm 25 secured to the panel I by rivets, or any other well known means.

The rack l3 reciprocates along the track 2| in sliding contact with the bar 26, which is made of conducting material and which is secured to the panel I in a plane parallel to the planes of the bar 22 and the track 2|. As shown in Fig. 3, the bar 26 and the bar 22 are of approximately the samelength. The rack I3 is made of conductive material, and, therefore, is adapted to transmit radio frequency currents from the winding 23 to the conductor bar 26.

In Fig. 4, I have diagrammatically shown a circuit representing a conventional type of tuned radio frequency broadcast receiver, wherein the means for collecting the signal energy is shown as an aperiodic antenna A, grounded, as at G, the conductor 23 being connected between the points 30 and 3|. In Fig. 3, it is pointed out that the contact post 30 is adapted for connection to an antenna and the contact post 3| to ground. The control electrode of the first radio frequency amplifier tube 32 is adjustably connected to the resistor 23, the connection to the said control electrode being made from the contact post 33 secured to the conductor bar 26, Fig. 3 pointing out that the said post 33 is connected tothe grid.

The output circuit of the first untuned stage containing the tube 32 is coupled to a plurality of tuned radio frequency amplifier stages, in a manner well known to those skilled in the art, and it is not thought necessary to describe the circuit any further than by stating that the output of the tuned stage is connected to a subsequent detector, a plurality of audio amplifier stages, and a loud speaker. Thus, it will be seen that if the rack I3 is reciprocated along the track 2| the potential on the grid of the tube 32 is varied, thereby controlling the volume ofthe receiver in a manner well known to those skilled in the art.

It is, of course, to be understood that while I have shown the rheostat arrangement disposed in an aperiodic antenna and an untuned radio stage for controlling the volume, or sensitivity of the receiver, it is readily adapted to be connected in any other circuit of a radio receiver, such as the filament heating circuit, or any other circuit the variation of which will affect the sensitivity of the receiver, the means specifically shown in this application being chosen because of its simplicity and ready adaptation to a modern broadcast receiver. It is essential to note merely that the fundamental principle involved in the present invention is the simple, or selective adjustment of the tuning instrumentality, or of the intensity instrumentality, with any additional instrumentality for varying a different electrical characteristic of a radio receiver by a single, continuous, manipulating motion. Furthermore, while I have shown the surface of the control sphere I as being made up of successive circles of teeth, it is clearly within the scopeof the present invention to provide a grooved, or serrated, surface adapted to mesh with the rack bars 5 and I3.

It is believed that with the aforegoing description of Figs. 1 to 4 inclusive, the operation of the uni-control means provided herein will be readily understood. When the control sphere I is rotated about pivots II and II, that is in a direction normal to the axis of the shaft 2, the teeth I4 will move the teeth ll of the rack 5, and the rotors of the gang condenser will thereby be adjusted to a desired tuning position. As the control sphere I is moved about the pivots 9, 9, that is in a horizontal direction, the teeth M will slide between the spaces l6 of the rack 5, and will, instead, contact with the teeth l of the rack l3, and thereby reciprocate the rack |3 along the winding 23 of the volume control instrumentality, thereby varying the sensitivity of the receiver.

It should, also, be obvious that if the control sphere is moved in a direction at approximately 45 degrees relative to the tuning and volume control motions mentioned above, the receiver can be simultaneously tuned and controlled as to sensitivity by a single, continuous motion. This is a result of the fact that part of such an angular displacement of the sphere causes rotation about the pivots 9, 9, while another part of such an angular displacement causes simultaneous rotation about the pivots whereby the rack 5 and the rack l3 are moved together.

In Fig. 5, there is shown a modified form of the invention wherein, instead of the opening I being of a circular shape to receive a portion of a spherical control, an elongated, slotted opening 42 is provided in the panel I, and a shaft 4| disposed for reciprocating, vertical motion provided therein. A knob 4|] is affixed to the protruding end of the shaft 4| for manipulation, while the end of the shaft 4| disposed to the rear of the panel I is formed with a flattened head 46 disposed within a hollow bearing 48. The bearing 48 is affixed to the web 48 of a circular rheostat, which comprises a thickened or flanged periphery 5|, made of insulating material, which periphery has wound thereon the resistance wire 53. One terminal 30 of the rheostat is connected to the antenna, and one terminal 3| to ground, as explained heretofore in connection with Figs. 3 and 4. A sliding contact arm 41 is mounted for slidable contact over the wire 53, and is affixed at one end thereof, adjacent bearing 48, to a sleeve 49, which sleeve is rigidly affixed to the shaft 4| by a set screw 50.

The gang condenser shaft 2 has mounted thereon, as explained heretofore, a plurality of rotors 3, and is rigidly affixed to the web 48' of the rheostat by means of a U-shaped connection or bracket 44. Each set of rotor plates 3 is adapted to cooperate with a set of stator plates 3' in a manner well known in the art, my invention not being limited to rotor or stator plates of any particular shape. One end of the bracket is bent into circular engagement, as at 43, with the shaft 2, whereby it is rigidly affixed to the shaft 2 in any suitable manner, while the other end thereof is bent at right angles thereto, as at 45, and is rigidly aifixed to a portion 52 of hub 53, by any well known means.

Thus, when the knob 48 is manipulated to rotate shaft 4|, due to the fact that the flattened head 46 of the shaft 4| is loosely mounted within the hollow space of the bearing 48, which bearing may also be considered as a hub portion of the web 48, the contact arm 41 will slide over the wires 53 because of the rigid attachment of the contact arm 4'! to the shaft 4| through the sleeve If the knob 48, on the other hand, is moved vertically along the slot 42, it is obvious that the bracket 44, the rheostat 5|, and the shaft 4| will act as a single, rigid means for rotating the shaft 2, and, consequently, adjusting the rotors 3 to any desired position. It will, also, be clear that the sensitivity of the receiver is varied by connecting the contact arm 4'7 to the grid of the first tube, as shown in Fig. 4. If the knob 45 is rotated, as it is being moved vertically through the 7 ..;'slot 42, then it follows that both the tuning and sensitivity of the receiver will be simultaneously adjusted by a single, continuous motion.

In Fig. 7, there is shown still another modification of the invention wherein the panel I is provided with a horizontal slot 50 disposed beneath an indicator screen 5|, which screen is provided with an index 35 marked thereon. Immediately behind the screen, there is disposed a dial drum 54, which drum is mounted upon the gang condenser shaft 2, and comprises a perforated periphery 54', there being a source of illumination 31 mounted behind the periphery whereby, if the perforations move by the source of illumination, images corresponding to the perforations projected upon the screen 5| appear thereon as scale indications 36 by virtue of the fact that the perforations in the periphery of the dial drum 54 are formed as scale indications.

Such construction is well known to those skilled in the art, and since the present invention does not depend on such indication, further details are not given, nor are any such indicators shown in the forms of the invention shown in Fig. 1 and Fig. 5. The gang condenser shaft 2 has mounted thereon a pulley wheel 55, which is preferably secured to the drum 54. Adjacent the drum 54, there is mounted a rotatable control shaft 60, this shaft being disposed in a plane normal to the condenser shaft 2 and central of the periphery portion of the drum dial 54. Thus, the control shaft is in vertical alignment, normally, with the periphery of the drum 54. One end of the shaft 60 is adapted to project through the slot 53 in panel I, being supported therein by roller |5 and bearing 38 of any suitable material. I prefer to make this bearing of a resilient material, such as rubber, for a purpose hereinafter described. The shaft 60 is provided with a control knob 6| at its outer end while the other end has secured thereto a relatively small pulley wheel 62.

Entrained around the pulleys 55 and 62 is a flexible belt, cord, or cable 63, which also passes over an idler pulley 64, this latter pulley being positioned in the manner shown in Fig. 7 so as to track the cable 63 upon the two pulleys. The idler pulley 64 is also positioned in such a manner as to tension the cable 63. The shaft 6|! is actually a split shaft, the small pulley 62 being mounted upon the smaller portion 60b of the split shaft and a flexible coupling 10 connecting the split portions 600. and 605.

This flexible coupling may be made of any desired flexible material, or it may be a short flexible shaft, it being only necessary to have the coupling 10 of such flexibility that the split portion 60a may be displaced along an arcuate path relative to the portion 60b. The resilient bearing 38, in addition to providing support to shaft portion 69a, also provides sufficient friction so that once shaft portion 60a has been moved to a desired position in slot 50, it will be frictionally retained in this position until moved once more.

A bearing frame H, which frame is rigidly affixed to the casing of the receiver, provides bearings for the shaft portion 69b, and thereby, while maintaining the portion 60b rigid when the shaft portion 60a is displaced relative thereto, permits rotation of the shaft portion 60b and the pulley 62 when the knob 6| is rotated.

In the aforegoing modification, the rheostat construction is secured by providing a resistance winding I2, the winding being connected at each of its terminals to a contact post, one of the posts 30 being adapted for connection to an antenna, while the other post 3| is to be connected to ground, as explained heretofore. The winding 12 is carried on curved bar 13 made of insulating material, which bar is rigidly affixed to therear of the panel I by arms 14, by any well known means, such as riveting. Upon the split shaft 60, there is mounted a roller contact I5, the contact being made of conducting material, and being mounted upon the split shaft in such a manner :the rear of panel I in the manner similar to the bar 13.

The operation of this modification of the invention will be obvious, it being merely necessary to explain that rotation of the knob 6| will result in rotation of the shaft 2 and consequent tuning of the circuit, while horizontal displacement of the knob 6| through the slot 50 will result in flexure of the coupling 10, with the result that the contact 15 will roll over the Winding 12, and

'.thereby vary the sensitivity of the receiver.

Obviously, the knob 6| can be rotated at the same time that it is being. horizontally displaced, and, in that case, both tuning and volume control will be simultaneously efiected by a single, continuous :motion.

In this modification, as well as in that shown in Fig. 1, it will be noted that although the various adjustable elements controlled by the tuning knob may be easily and quickly adjusted either independently of one another or simultaneously,

as may be desired, the position of each adjustable element is fixed with relation to some outside point or element, as, for example, the panel. Furthermore, the modification shown in Fig. 1

.has also the tuning knob itself so fixed. Thus, in

Fig. 1, although the condenser represented by the rotors 3, the winding 23 with its cooperating rack I3, and the knob 1 are all adjustable, the physical location of each as a unit remains fixed 501, with respect to panel I.

Similarly, in Fig. 7, the condenser shown at 3 and the winding 12 with roller 15 remain, as units, fixed in their location with respect to the panel, and by means of my invention, it is possible to 551 adjust the various adjustable elements without at any time disturbing or changing their location during adjustment. Hence, by this construction, it is possible to easily and conveniently provide, in a radio receiver wherein a gang of :condensers is incorporated, a true uni-control for controlling both the selectivity and sensitivity of the receiver, either separately or simultaneously, at will, the constant moving about of a'cumbersome unit being obviated.

While I have described the construction and operation of the invention with relation to the variation of two electrical instrumentalities, one of which comprises a tuning instrumentality, and the other one an instrument for varying the sensitivity of a receiver circuit, it is to be clearly understood that the invention is not limited to such instrumentalities but may be employed for the selective, or simultaneous variations of instrumentalities of diverse electrical character- 75 ,cistics.

Furthermore, while I have indicated and described several arrangements for carrying my invention into efiect, it will be apparent to one skilled in the art that my invention is by no means limited to the particular organizations shown and described, but that many modifications may be made without departing from the scope of my invention as set forth in the appended claims.

What I claim is:

1. In a radio receiver having a plurality of variable elements, a spherical unitary control knob mechanically coupled to said elements, and a mounting for said control knob comprising bearings having their axes at right angles to each other whereby movement of said knob about one of said axes permits adjustment of one of said variable elements, and movement of said knob about the other of said axes permits adjustment of another of said variable elements.

2. In a radio receiver, in combination, a'plurality of adjustable elements, a single control knob for said elements, a mounting ring for said control knob, means for mounting said knob for movement relative to the ring about an axis to adjust one of said adjustable elements, and means for mounting said mounting ring for movement, together with said control knob, about another axis whereby to control another of said adjustable elements.

3. In a radio receiver, in combination, a plurality of adjustable elements, a single control knob for said elements, a mounting ring for said control knob, means for mounting said knob for movement relative to the ring about an axis to adjust one of said adjustable elements, and means for mounting said mounting ring for movement, together with said control knob, about a second axis at right angles to said first axis whereby to control another of said adjustable elements.

4. In combination, in a radio receiver, a tuning means, a volume control means, a spherical adjusting device, means for supporting said device for rotation about a pair of normal axes, said device being mechanically coupled to said tuning and volume control for manual adjustment of said tuning and volume control means.

5. In combination, a variable condenser, a variable resistor, a spherical control means mechanically coupled to the condenser and resistor, and means supporting the control means for rotation about a pair of normal axes for independent adjustment of the resistor and condenser.

6. In combination, a variable condenser, a variable resistor, a sphere mechanically coupled to the condenser and resistor, and means supporting the sphere for rotation about at least two perpendicular axes for independent adjustment of the resistor and condenser.

7. In combination, a variable condenser, a variable resistor, a spherical control means mechanically coupled to the condenser and resistor, and means supporting the control means for rotation about at least two normal axes for independent or simultaneous adjustment of the resistor and condenser.

8. In a radio instrument, the combination of a tuning device, an amplifier control means, a pivotally mounted gimbal ring, a sphere, a pair of pivots secured to said ring and engaging said sphere to provide journal means therefor, means connecting said tuning device and sphere and a separate means connecting said amplifier control means and said sphere.

9. In combination in an electrical control means, a tuning device, an amplifier control) means, an adjusting means mounted for rotation about either one of a pair of normal axes which intersect at a point within the adjusting means, and means including speed reducing gearing in constant engagement with said adjusting means serving to mechanically connect it with said tuning device and amplifier control means simultaneously.

10. In combination in an electrical control means, a first device to be adjusted, a second device to be adjusted, a rack connected to each of said devices, a gear in constant engagement with said racks and means for mounting said gear so arranged that one of said racks may be moved independently of the other or both of said racks moved simultaneously by rotation of said gear.

11. In a radio instrument, the combination of a rotatable tuning means, a resistor, a contact adjustable along said resistor, a substantially spherical control member provided with gear teeth on its surface, means pivotally mounting said control member, an oscillatable rack constantly engaging the gear teeth of said control member, means mechanically connecting said: rack and said tuning means and means mechanically connecting said adjustable contact and said spherical control member including a second rack in constant engagement with the gear teeth of said control member.

MORRIS A. RABKIN. 

